1. Field of the Invention
The present invention is related to information handling systems, and, more specifically, to automatic adjustment of over current protection in a degraded mode of a power supply of the information handling system.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users are information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes, thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems, e.g., computer, personal computer workstation, portable computer, computer server, print server, network router, network hub, network switch, storage area network disk array, RAID disk system and telecommunications switch.
Many of the information handling systems are being placed in remote locations or may be unattended for long periods of time. The information handling systems are also being designed to meet government and industry requirements of being able to be placed into a low power standby mode, either automatically (after a time period of inactivity) or by remote command. However, some modules (circuits) of the information handling system must remain powered so as to allow wake-up of the information handling system from the low power standby mode when required by a user. As the information handling systems become more sophisticated and powerful, and/or multiple information handling systems share a common power supply unit (PSU), standby power requirements have increased to the point where the PSU requires airflow for cooling of its components.
In the case of a cooling fan failure in the PSU, the PSU standby voltages must be shut down in order to prevent catastrophic failure of the PSU and/or safety rule violations when the PSU components overheat. A PSU has a well defined safety specification that specifies maximum allowable values for over current protection, over temperature protection, short circuit protection, over voltage protection, under voltage protection and the like. In order to meet PSU safety specifications and/or prevent catastrophic PSU failures because of high component temperatures caused by cooling fan failures, PSU designers have used the following procedures: (1) Shutdown of the PSU voltages used for standby conditions. This is the simplest and least costly, but does not allow the information handling system to run in standby so that there can be remote access thereof. (2) Over temperature protection of the PSU standby power circuits. This allows the information handling system to be in a standby mode until a PSU standby power components begins to overheat, then the PSU must be shut down. This is the most robust for available standby operation, but is also the most costly since temperature sensors and discreet temperature monitoring circuits are required. (3) Shutdown of the PSU voltages used for standby conditions for a time defined by the time it takes to reach safe standby operation based upon worst case component cool down of overheating conditions. This may allow information handling system remote standby availability, but without the costly components necessary for the over temperature protection discussed hereinabove.
Therefore, what is needed is a solution for keeping maximum availability of a PSU standby voltage output(s) operational during a cooling fan failure while minimizing the cost and number of components required.